Food and Nutrition Acid Test FOSS food and Nutrition, TESLA Science Notebooks.

Food and NutritionAcid Test

FOSS food and Nutrition, TESLA Science Notebooks

BIG IDEA:Foods contain specific materials such as fats, proteins, sugars, and acid that work together to create healthy or unhealthy eating choices.

Engaging ScenarioThe nutritionist for the Lewiston School District was happy to receive your results on the sugar test. She has been so impressed with your data that she would like you to conduct one more final investigation. Certain foods contain acid and she would like us to test different fruits to see if acids are present. There is one acid in particular, Ascorbic Acid, which is an essential nutrient for humans.

To help us, she has sent a powder called baking soda and two liquids called vinegar and indophenol that we can use in our tests.

The results of your investigation will help her determine which foods should be added to the menu so students may receive a balanced diet with essential nutrients.

What do we need to investigate?What is the problem that needs to be solved?

Word Wall

Nutrient: Important chemicals found in food that helps keep an organism alive and active.

Acid: a common, naturally occurring class of chemicals. Acids are commonly added to processed foods for taste and as a preservative.

Focus Question:

How can we … use baking soda, vinegar, and indophenol to determine if certain fruits contain acid?

“What does the school nutritionist want us to do?”-- Use the materials provided to test certain fruits for the presence of acid.-- Help her determine which foods should be added to the menu

“Discuss with your group what we need to investigate and record it as the FOCUS QUESTION. This is the problem we are going to investigate and solve.”

Background Knowledge:

Scientists typically reference the acidity of a solution using what is called a pH scale. The pH scale ranges from 0 to 14. It measures the acidity or basicity of a solution. A pH of 7 means it is a neutral solution (in the middle). Pure distilled water has a pH of 7. It is neither acidic nor basic. A pH of less than 7 means the solution is acidic. A pH of more than 7 means the solution is basic (not acidic). The less pH, the more acidic the solution is. The more pH, the more basic the solution is.

Acidic Solutions Neutral Basic Solutions

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Lemon Juice Vinegar Pure

Water Baking Soda

Ammonia


“Where have you seen these two materials before?”

“What were they used for?”

“The district nutritionist sent use vinegar and baking soda to help with our tests. How can we describe these two materials according to the pH scale? ---Vinegar is an Acidic Solution---Baking Soda is a Basic (non acidic) Solution


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Water Baking Soda

Ammonia

Prediction:

I would like you to record a prediction in your science notebook. Discuss with your group what you think will happen when I add 5-ml of vinegar to a cup that contains 1-ml of baking soda.

EXAMPLE Prediction:

I think that if we _______________________________________

because ______________________________________________

Part One: Acid IndicatorMaterials per Test/Group:

• Syringe (Specially designed Syringe for vinegar tests) • Long handled 1-ml spoon• 1-ml of baking soda• 5-ml of vinegar• 1 cup

1. Measure one level spoon of baking soda into an empty cup.2. Demonstrate with students how to use the syringe to accurately

measure 5-ml of vinegar. When the flat part of the triangular notch is even with the end of the syringe barrel, the syringe holds exactly 5-ml.

3. Squirt 5-ml of vinegar into the cup

Record Observations in the Science notebook using detailed drawings with labels and explanations.

Observations:

“What changes did you see when I combined the two materials?” The mixture starts to fizz or bubble

“Why do you think this happened?” When we mixed the two materials together a chemical reaction occurred. The fizzing, bubbling, change of smell, and foaming are all evidence of a chemical reaction. The acid and baking soda reacted when mixed.

Chemical Reaction: a change that occurs as a result of mixing two or more materials together. A reaction forms new materials with different properties from the original.

Carbon Dioxide: a colorless, odorless gas. It is typically produced by living organisms, and some chemical reactions.

Observations:

“How was this reaction different from the one we witnessed in our sugar tests?”

In the sugar test the carbon dioxide was produced as a product of the yeast, a living organism, turning a food source into energy. The yeast was metabolizing its energy source.

In this reaction vinegar and baking soda are not living organisms so nothing is being metabolized. Instead the carbon dioxide is a product of a chemical reaction. The two ingredients are reacting to form a new material with different properties. “Was your initial prediction supported?”

Part One: Acid Indicator“Lets try the reaction again, but this time we are going to use a different bottle and set-up”Materials per Test/Group:

• Syringe (Specially designed Syringe for vinegar tests) • Long handled 1-ml spoon• 1-ml of baking soda• 5-ml of vinegar• 1 Reaction bottle• 1 Rubber stopper

1. Measure one level spoon of baking soda into the reaction bottle. Insert the rubber stopper tightly into the bottle with a twisting motion.

2. Draw 5 ml of vinegar into the syringe. Push and hold the tip of the syringe into the hole in the rubber stopper.

3. Squirt the vinegar into the bottle. Don’t pull the syringe out of the stopper, and don’t hold the plunger down.

Record Observations in your Science notebook using detailed drawings with labels and explanations.

Observations:

“What happened when we squirted vinegar into the reaction bottle?”The syringe plunger went up or rose.

“Why did this happen?”Gas produced from the chemical reaction of vinegar and baking soda filled the syringe causing the plunger to rise. The previous test created gas, but we couldn’t see it. The gas just mixed into the air. The gas that is produced is carbon dioxide, the same gas that was produced in our sugar tests when the yeast metabolized sugar. In that investigation carbon dioxide was produced as a product of respiration from a living organism. In this investigation carbon dioxide is being produced as a product of a chemical reaction. Neither the baking soda nor vinegar are living organisms.

Prediction:

“Lets try the reaction again, but this time we are going to use 5-ml of water instead of 5-ml of vinegar. What do you think will happen?”

EXAMPLE Prediction:

I think that if we _______________________________________

because ______________________________________________

Baking Soda and WaterMaterials per Test/Group:

• Syringe (Specially designed Syringe for vinegar tests) • Long handled 1-ml spoon• 1-ml of baking soda• 5-ml of water• 1 Reaction bottle• 1 Rubber stopper

1. Measure one level spoon of baking soda into the reaction bottle. Insert the rubber stopper tightly into the bottle with a twisting motion.

2. Draw 5 ml of water into the syringe. Push and hold the tip of the syringe into the hole in the rubber stopper.

3. Squirt the water into the bottle. Don’t pull the syringe out of the stopper, and don’t hold the plunger down.

Record Observations in your Science notebook using detailed drawings with labels and explanations.

Observations:

“What happened when we squirted the water into the reaction bottle?”Nothing, the water soaked into the baking soda, but a gas producing reaction does not occur.

“Was your initial prediction supported?”

“Why did this happen?”Mixing water and baking soda does not produce a chemical reaction. The water did not react with the baking soda. We know this because the solution did not fizz, bubble, smell, or produce gas. The result of mixing these two substances does not produce a new substance.

Observations:

“Why does the baking soda react with the vinegar, but does not react with the water?


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Water Baking Soda

Ammonia

Baking soda can be used as an indicator of acidic solutions. When the baking soda is mixed with vinegar a reaction occurred because vinegar is an acidic solution. When the baking soda was mixed with water, no reaction occurred because water is a neutral solution neither acidic nor basic.

Prediction/Quick Write:

Why do you think the district nutritionist sent us baking soda, if she wants us to determine if acids are present in fruit juice? Justify your prediction with a because statement.

I think that the district nutritionist sent us baking soda to determine if acids are present in fruit juice because…

Part Two: Acid in Fruit

We now know that baking soda can be used as an indicator to determine if acid is present in a solution. We know this because when we mixed baking soda with vinegar, an acidic solution, a chemical reaction occurred producing carbon dioxide. When we mixed baking soda with water, a neutral solution, no reaction occurred.

I sent your results to the food nutritionist and she was very happy to see that you identified baking soda as an indicator of acid in foods. She sent us some more materials; a 50/50 solution of water and vinegar, and squeezed juice from limes, grapefruits, oranges, and lemons. She is hoping that you could help her determine if certain fruits contain acid. She would also like to know if there is a way to determine if certain fruits contain more acid than others.


Focus Question:

How can we … use baking soda to determine if certain fruits contain acid?

“What does the school nutritionist want us to do?”-- Use the materials provided to test certain fruits for the presence of acid.-- Help her determine if certain fruits contain more acid than others.

“We already know that baking soda is an indicator for acid, how we can solve the new problem presented to us by the district nutritionist.”

I think that if we… because ....

Acid in Fruit -- Designing a Fair Test

What are you going to change What are you going to keep the same

The 5-ml solutions tested50/50 vinegar and water

Orange juiceLemon juice

Grapefruit juiceLime juice

Testing Method:1-ml of baking soda

5-ml of solution testedClean reaction bottle

Rubber stopperSyringe

Which fruit juices do you think will react with the baking soda? Will some react more than others? Justify your prediction with a because statement.

I think that… because…

Acid in Fruit Test

We will follow the same procedure we used in the vinegar and water test except this time we will test and record the results from other 5-ml solutions. The variable we are testing in this investigation is different solutions.

After you complete each test I would like you to record your results using this chart. Identify how much the plunger in the syringe has rose for each solution tested.

“What causes the plunger to rise?”

Making Meaning of our Results

“Was your initial prediction supported?”

“What happened when you squirted the different solutions into the reaction bottle containing baking soda?”

“Which solutions tested reacted with the baking soda? What does this reaction tell us?”

“The nutritionist was also hoping that we could identify if certain solutions contain more acid than others. Does your data provide us with information that could help us identify if some fruit juices contain more acid than others?”

“Many of you have eaten these fruits before or drank their juice. What did they taste like? Do you think there could be a relationship between a fruits taste and acid concentration?”

Concentration: the amount of material dissolved in a liquid. The more material dissolved in the liquid, the more concentrated the solution.


Develop a claim that identifies a relationship between the amount of acid found in fruit juices and the amount of carbon dioxide produced when a fruit juice is mixed with baking soda.

I claim that… I claim this because… I claim that fruit juices with higher concentrations of acid produce more carbon dioxide when mixed with baking soda than fruit juices with lower concentrations of acid. I claim this because… Develop a claim that identifies the relationship that exists between sour tastes of fruit and acid concentration?

I claim that… I claim this because…I claim that fruits with sour taste have a higher concentration of acid. I claim this because the fruits tested that produced the most carbon dioxide are also the sourest tasting.

Part Three: Vitamin-C SearchFrom our investigations so far we know that citrus fruits contain acid and some citrus fruits contain a higher concentration of acid than others, but our tests did not tell us what kind of acid was in the fruits. The nutritionist told us earlier that there are different types of acid and one acid in particular, Ascorbic Acid, is an essential nutrient for humans. Ascorbic acid is commonly called, vitamin C. Humans cannot make vitamin C in their bodies, so they must get this nutrient by eating foods or supplements that contain vitamin C.

We are going to use the indophenol liquid the nutritionist sent us to test some more foods because indophenol is an indicator for vitamin C. She is hoping that you could help her determine if certain fruit juices contain vitamin C. She would also like to know if there is a way to determine if certain fruit juices contain higher concentrations of vitamin C than others. The results of your investigation may help determine which fruit juices would be healthy and beneficial additions to the school lunch program.


Word Wall

Indophenol: Can be used as an indicator of vitamin C in foods

Ascorbic Acid: Vitamin C, an essential acid in human nutrition

Focus Question:

How can we … determine if certain fruit juices contain vitamin C and if some fruit juices contain higher concentrations of vitamin C than others.

“What does the school nutritionist want us to do?”-- Determine if certain fruit juices contain vitamin C.-- Determine if certain fruit juices contain higher concentrations of vitamin C.


If you were to drink this 175-ml cup of vitamin-C solution your body would receive the appropriate amount of vitamin-C it needs to stay healthy for one day.

In nutrition this is called RDA the recommended daily allowance. The solution in the jar was created by mixing 700-ml of water with a 250-mg vitamin-C tablet. We mixed and diluted the vitamin C concentration from the tablet with 700-ml of water because one of these tablets provides more than 4 times the recommended daily allowance.

700-ml of the solution divided by 4 is 175-ml or one daily serving

Vitamin-C Test:When we test fruit juices for the presence of vitamin-C we are going to compare them to our recommended vitamin-C solution.1. Squirt exactly 10-ml of the blue indophenol indicator from the

dispensing bottles into a reaction bottle. (Fill to the 10-ml line)

2. Use a dropper to put drops of the material you are testing (Vitamin-C solution from your 175-ml cup) into the reaction bottle. Add one drop at a time. Gently swirl the bottle after each drop.

3. Count the number of drops needed to make the blue indicator colorless. Place the reaction bottle on white paper for contrast.

(There should be no hint of color)4. Record the number of drops needed.5. Dump the materials from the reaction bottle into a 1-liter

waste container, and rinse the reaction bottle thoroughly before testing the next juice.

Observations/Prediction

What is happening? Why did the blue indophenol indicator change color when we added drops from the Vitamin-C solution?The blue indophenol indicator is reacting with the vitamin-C present in the drops of vitamin-C solution we added. The reaction causes the indophenol to change from blue to clear.

I think that we … because....

Develop a prediction with your group -- how can we use an indophenol test to determine if certain fruits juices contain vitamin C and if some fruit juices contain higher concentrations of vitamin C than others?

Vitamin-C in Fruit Designing a Fair Test

What are you going to change What are you going to keep the same

The solutions testedVitamin-C Solution

Fruit Juices Collected

Testing Method:10-ml of blue indophenol indicator

Testing dropperSwirl after each drop

Fruit juices that contain a higher concentration of vitamin-C will take fewer drops to change the color of the indophenol indicator. Fruit juices that contain lower concentrations of vitamin-C will take more drops to change the color of the indophenol indicator. Which fruit solutions do you think will contain the highest and lowest concentrations of vitamin-C? Justify your prediction with a because statement. I think that… because…

Making Observations and Collecting Accurate Data:

Source of Vitamin-C Drops needed to Clear 10-ml of Indophenol Indicator

Vitamin-C Solution (RDA Concentration)

Other fruit juices collected

Math Extension:Calculating RDA % of Vitamin – C in fruit drinks

Since we know that 175ml of our standard vitamin-C solution provides 100% of our RDA, can we calculate (or estimate) the percentage of RDA in one serving of the fruit drinks we tested?

Hint: If the vitamin-C solution took 20 drops to neutralize 10ml of indophenol indicator and a sample of fruit juice takes 10 drops to neutralize 10ml of indophenol indicator, what is the % of RDA in the fruit juice tested?

20 drops is 100% RDA 10 drops is ___________RDA200%Less drops means there is a higher concentration of vitamin-C in the solution. If the solution requires half the amount of drops to change the indicator, there is twice as much vitamin-C in the solution.


“What is Vitamin-C?”Ascorbic Acid, an essential nutrient humans must consume

“What indictor is used to detect vitamin-C?”Indophenol

“What is the evidence that vitamin C is present?”When enough juice containing vitamin-c is added to the

indophenol solution, the solution changes from blue to clear

“Which solutions tested reacted with the indophenol indicator? What does this reaction tell us?”

The solution/juice added contains some concentration of vitamin-C.


“The nutritionist was hoping that we could identify if certain juices contain more vitamin-C than others. Does your data provide us with information that could help us identify which fruit juices contained the most vitamin-C, which contained the least?” Juices that contain higher concentrations of vitamin-c will turn the indicator colorless with just a few drops; a juice with a small amount of vitamin-C will require many more drops.

“How do you know?”Our control was a solution that contained the recommended daily allowance of vitamin-C. Juices that required less drops to turn the indicator colorless contain a higher than RDA concentration of vitamin-C; juices that required more drops contain a lower than RDA concentration of vitamin-C.

What recommendations would you provide the district nutritionist for offering juices that provide good sources of vitamin-C?

Making MeaningThe Acid Tests

How can baking soda be used to indicate the presence of acid in foods?

What relationship exists between acid concentration in fruit juice and the amount of carbon dioxide produced when fruit juice and baking soda are mixed?

What relationship exists between sour tastes of fruit and acid concentration?

How can we determine which fruit drinks have the highest concentration of Vitamin C?

Claims and Evidence:

Based on what you have learned from your investigation of acids, you need to record some claims and evidence statements in your science notebook… Your evidence must be based on your data!

I claim that… I know this because…

Possible Example:I claim that baking soda can be used as an indicator for the presence of acid in foods. I know this because…

I claim that fruit juices with higher concentrations of acid produce more carbon dioxide when mixed with baking soda. I know this because…

11/8

November 2011REFLECTION AND CONCLUSION

• What did you learn…?

• What really surprised you…?

• What new questions do you have…?

• What would you like to know more about…?

Food and Nutrition Acid Test FOSS food and Nutrition, TESLA Science Notebooks.

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Transcript of Food and Nutrition Acid Test FOSS food and Nutrition, TESLA Science Notebooks.